Plasma etching method

Abstract

A plasma etching method employing a parallel-plate type plasma etching device which comprises a reaction chamber, a substantially plate-like ground electrode and a substantially plate-like counter electrode both disposed in parallel with each other within the reaction chamber. The method includes the steps of placing a material to be etched on the ground electrode and carrying out an electric discharge with a spacing between the electrodes being substantially 3 to 10 mm. Etching is performed exactly at a high speed in an anisotropic form without requiring a high degree of vacuum.

We claim: 
     
       1. A plasma anisotropic etching method employing a parallel-plate type plasma etching device which comprises a reaction chamber, a substantially plate-like ground electrode and a substantially plate-like counter electrode both disposed in parallel with each other within said reaction chamber, the method comprising the steps of: placing a material to be etched on said ground electrode;   carrying out an electric discharge with a spacing (s) between both said electrodes such that the spacing (s) is greater than 3 mm and no greater than 10 mm (i. e., 3 mm ≦S<10 mm); and   the plasma anisotropic etching is carried out with the same treating gases, pressure and radio-frequency power as in a plasma isotropic etching.   
     
     
       2. A plasma etching method according to claim 1, wherein: said counter electrode has an uneven discharge surface.   
     
     
       3. A plasma etching method according to claim 2, wherein: said counter electrode has a substantially concave discharge surface.   
     
     
       4. A plasma etching method according to claim 2, wherein: said counter electrode has a substantially convex discharge surface.   
     
     
       5. A plasma etching method according to claim 1, wherein: the treating pressure is in the range of 0.1 to 10 Torr.   
     
     
       6. A plasma etching method according to claim 5, wherein: the treating pressure is in the range of 0.2 to 1.2 Torr.   
     
     
       7. A parallel-plate type plasma etching device comprising: a reaction chamber;   a substantially plate-like ground electrode on which a material to be etched is placed;   a substantially plate-like counter electrode;   said ground electrode and said counter electrode being disposed substantially in parallel with each other within said reaction chamber;   said counter electrode having a discharge surface on which are formed a plurality of concentric projections;   said projections having relatively different heights so as to define a substantially uniformly uneven configuration over substantially the entirety of said discharge surface; and   said counter electrode has an area width substantially equal to that of said material to be etched.   
     
     
       8. A parallel-plate type plasma etching device comprising: a reaction chamber;   a substantially plate-like ground electrode on which a material to be etched is placed;   a substantially plate-like counter electrode;   said ground electrode and said counter electrode being disposed substantially in parallel with each other within said reaction chamber;   said counter electrode having a discharge sruface on which are formed a plurality of concentric projections;   said projections having relatively different heights so as to define a substantially uniformly uneven configuration over substantially the entirety of said discharge surface;   said counter electrode has an area width substantially equal to that of said material to be etched; and   a central one of said projections has a relatively smallest height, while the remaining ones of said projections have heights which gradually increase toward the outermost projection, so as to define a substantially concave configuration.   
     
     
       9. A parallel-plate type plasma etching device comprising: a reaction chamber;   a substantially plate-like ground electrode on which a material to be etched is placed;   a substantially plate-like counter electrode;   said ground electrode and said counter electrode being disposed substantially in parallel with each other within said reaction chamber;   said counter electrode having a discharge surface on which are formed a plurality of concentric projections;   said projections having relatively different heights so as to define a substantially uniformly uneven configuration over substantially the entirety of said discharge surface;   said counter electrode has an area width substantially equal to that of said material to be etched; and   a central one of said projections has a relatively largest height, while the remaining ones of said projections have heights which gradually decrease toward the outermost projection, so as to define a substantially convex configuration.   
     
     
       10. A parallel-plate type plasma etching device comprising: a reaction chamber;   a substantially plate-like ground electrode on which a material to be etched is placed;   a substantially plate-like counter electrode;   said ground electrode and said counter electrode being disposed substantially in parallel with each other within said reaction chamber;   said counter electrode having a discharge surface on which are formed a plurality of concentric projections;   said counter electrode has an area width substantially equal to that of said material to be etched; and   said projections are each substantially 0.5 mm high and spaced at intervals of substantially 1 mm so as to define a substantially uniformly uneven configuration over substantially the entirety of said discharge surface.